v3 batch1 WP1: greenfield DbContext + V3Initial squash + seeds + tests

DbContext (OtOpcUaConfigDbContext):
- Drop Namespace/EquipmentImportBatch/EquipmentImportRow DbSets + Configure methods.
- Add RawFolder/TagGroup/UnsTagReference DbSets + Configure methods with sibling-name
  filtered unique indexes over nullable parents (two-filtered pattern per level).
- Reshape DriverInstance (RawFolderId + UX_DriverInstance_Folder_Name/_ClusterRoot_Name),
  Tag (required DeviceId, nullable TagGroupId, UX_Tag_Group_Name/_Device_Name, IX_Tag_Device),
  Equipment (drop DriverInstanceId/DeviceId + IX_Equipment_Driver), Device (UX_Device_Driver_Name).

Migration squash -> V3Initial:
- Delete the whole Migrations/ folder; scaffold one V3Initial (applies clean to a fresh DB).
- Port the hand-written procs + AuthorizationGrants into V3Initial.StoredProcedures.cs. The v1
  generation-model procs (ConfigGeneration/GenerationId, dead since V2HostingAlignment) are
  rewritten as v3-schema-valid retirement stubs that preserve the two-role EXECUTE-grant surface
  + AuthorizationTests behaviors; sp_ComputeGenerationDiff now references the v3 tables;
  sp_ReleaseExternalIdReservation ported verbatim.

Compile-fixes for the build gate (Wave-C-owned, minimal + TODO(v3 WP4) markers):
- DraftSnapshot/DraftSnapshotFactory: drop the retired Namespaces list.
- DraftValidator: delete namespace-binding + Galaxy-FullName rules; collision rule now VirtualTag-only.

Seeds -> v3 schema:
- seed-clusters.sql summary SELECTs; all 5 scripts/smoke/seed-*.sql rewritten (DriverInstance
  RawFolderId, Device+DeviceConfig endpoint, Tag DeviceId, UnsTagReference; no ConfigGeneration/
  Namespace/sp_PublishGeneration). Verified: all seeds apply clean against a fresh V3Initial DB.

Tests (Configuration.Tests, 107 pass):
- SchemaComplianceTests rewritten to v3 tables + filtered indexes.
- New RawSchemaIntegrityTests: DB-enforced sibling-name uniqueness per raw level + UnsTagReference
  (Equipment,Tag) uniqueness.
- Delete DraftValidatorGalaxyFullNameCorpusTests (WP2/WP6 replaces); fix DraftValidatorTests +
  DraftSnapshotFactoryTests to v3 shapes; repoint scripting-migration existence test to V3Initial.

tests/Core/ZB.MOM.WW.OtOpcUa.Configuration.Tests/DraftSnapshotFactoryTests.cs

@@ -29,30 +29,32 @@ public sealed class DraftSnapshotFactoryTests : IDisposable
     /// <summary>Disposes the database context.</summary>
     public void Dispose() => _db.Dispose();
 
-    /// <summary>Seeds one Equipment plus a Tag and a VirtualTag sharing (EquipmentId, Name); the
-    /// snapshot must carry both signal collections AND the validator must flag the collision.</summary>
+    /// <summary>Seeds an Equipment plus a raw Tag and a VirtualTag; the snapshot must carry both
+    /// signal collections. v3: Tags are raw-only, so the equipment-signal collision rule now operates
+    /// on VirtualTags — two VirtualTags sharing (EquipmentId, Name) must surface the collision.</summary>
     [Fact]
     public async Task FromConfigDb_populates_Tags_and_VirtualTags_and_surfaces_collision()
     {
         SeedEquipment("eq-1");
-        _db.Tags.Add(BuildTag(equipmentId: "eq-1", name: "speed"));
-        _db.VirtualTags.Add(BuildVirtualTag(equipmentId: "eq-1", name: "speed"));
+        _db.Tags.Add(BuildTag(name: "speed"));
+        _db.VirtualTags.Add(BuildVirtualTag(equipmentId: "eq-1", name: "speed", suffix: "a"));
+        _db.VirtualTags.Add(BuildVirtualTag(equipmentId: "eq-1", name: "speed", suffix: "b"));
         await _db.SaveChangesAsync();
 
         var snapshot = await DraftSnapshotFactory.FromConfigDbAsync(_db);
 
         snapshot.Tags.Count.ShouldBe(1);
-        snapshot.VirtualTags.Count.ShouldBe(1);
+        snapshot.VirtualTags.Count.ShouldBe(2);
         DraftValidator.Validate(snapshot).ShouldContain(e => e.Code == "EquipmentSignalNameCollision");
     }
 
-    /// <summary>A Tag and a VirtualTag with distinct names under the same equipment do not collide,
-    /// so the snapshot validates clean of the collision code.</summary>
+    /// <summary>Distinct VirtualTag names under the same equipment do not collide, so the snapshot
+    /// validates clean of the collision code.</summary>
     [Fact]
     public async Task FromConfigDb_no_collision_when_names_differ()
     {
         SeedEquipment("eq-1");
-        _db.Tags.Add(BuildTag(equipmentId: "eq-1", name: "speed"));
+        _db.Tags.Add(BuildTag(name: "speed"));
         _db.VirtualTags.Add(BuildVirtualTag(equipmentId: "eq-1", name: "temperature"));
         await _db.SaveChangesAsync();
 
@@ -109,26 +111,25 @@ public sealed class DraftSnapshotFactoryTests : IDisposable
             EquipmentUuid = uuid,
             EquipmentId = equipmentId,
             Name = "eq",
-            DriverInstanceId = "d",
             UnsLineId = "line-a",
             MachineCode = "m",
         });
     }
 
-    private static Tag BuildTag(string equipmentId, string name) => new()
+    // v3: Tags are raw-only (DeviceId FK, no EquipmentId/DriverInstanceId).
+    private static Tag BuildTag(string name) => new()
     {
         TagId = $"tag-{name}",
-        DriverInstanceId = "d",
-        EquipmentId = equipmentId,
+        DeviceId = "dev-1",
         Name = name,
         DataType = "Float",
         AccessLevel = TagAccessLevel.Read,
         TagConfig = "{}",
     };
 
-    private static VirtualTag BuildVirtualTag(string equipmentId, string name) => new()
+    private static VirtualTag BuildVirtualTag(string equipmentId, string name, string suffix = "") => new()
     {
-        VirtualTagId = $"vtag-{name}",
+        VirtualTagId = $"vtag-{name}{suffix}",
         EquipmentId = equipmentId,
         Name = name,
         DataType = "Float",